DESCRIPTION: (Applicant's Abstract) The persistence and prevalence of adolescent substance use has become a national health problem. Tobacco use in particular is increasing among adolescents. Nearly two-thirds of all adolescents smoke at least one cigarette before the age of 18, more than doubling an adolescent's risk for regular adult smoking (USDHHS, 1994). While the problem is known to be pervasive, there has been much less research on the development of effective treatments for this heterogeneous population, particularly sub-groups within the substance using adolescent population, such as juvenile offenders. Research with adult substance users has shown that Motivational Interviewing is effective in reducing the severity and frequency of substance use. MI has also shown promise with particular types of adolescent substance use, such as cigarette, alcohol, and marijuana use. It has not yet been tested with delinquent adolescents, a group for whom developing successful treatments has been particularly difficult. The proposed study will test the effectiveness of a brief intervention, Motivational Interviewing (MI), for tobacco-using juvenile offenders and will test whether comorbid problems, such as depression, moderate outcomes. In a controlled, randomized 2 (Intervention: Motivational Interviewing vs. Standard Education) x 3 (Time: Baseline, 30 day, 6 month) mixed factorial design we will test the hypothesis that MI will increase motivation to change tobacco use and reduce frequency and quantity of tobacco use at follow-up intervals. Dependent variables include frequency and quantity of tobacco use, motivation to change behavior, and biochemical measures of tobacco use such as expired CO and salivary cotinine. We will also test our second hypothesis that comorbid problems moderate treatment outcome. Long term objectives include learning more about the effectiveness of MI as a cost-effective, widely applicable technique to increase motivation to reduce substance use and advancing a conceptualization of how comorbid problems may influence the course and outcome of treatment.